Process for Synthesis of a Layered Oxide Cathode Composition

ABSTRACT

A method for preparing a layered oxide cathode using a two step calcination procedure, wherein the first step includes pre-calcination utilizing a rotary calciner.

GOVERNMENT SUPPORT

The U.S. Government has a nonexclusive nontransferable irrevocablepaid-up license in this application throughout the world under the termsof DE-EE0000563 awarded by the U.S. Department of Energy and per 48 CFR952.227-13(k).

BACKGROUND

Lithium-ion batteries are composed of three components—an anode, acathode, and an electrolyte that allows Li ions to flow from the anodeto the cathode (discharging), or vice versa (charging). There are manyknown cathode materials, including, for example, LiCoO₂, LiMn₂O₄,LiNiO₂, LiFePO₄, Li₂FePO₄F, Li(Ni_(1/3)Co_(1/3)Mn_(1/3))O₂, andLi(Li_(a)Ni_(x)Co_(y)Mn_(z))O₂.

Although these cathode materials are well known, syntheses of thesecathodes can be costly and time consuming. For example, synthesis of alayered oxide cathode material, such as Li(Li_(a)Ni_(x)Co_(y)Mn_(z))O₂,wherein lithium carbonate is the Li source, requires calcination atgreater than 700° C. for 20 to 30 hours in a ceramic saggar in either abox type furnace, a pusher type tunnel kiln, or a roller hearth kiln(RHK). In certain instances, these materials can require double passcalcination with a milling step required between the first and secondcalcinations to ensure complete reaction of the starting materials andgood product homogeneity.

In view of the attendant costs associated with long calcination timesfor the production of layered oxide cathodes, it would be desirable todevelop a process that operated at lower temperature, required lesscalcination time, or both.

SUMMARY

The present disclosure provides a process for the synthesis of a layeredoxide cathode composition for use in secondary Li-ion batteries. Theprocess comprises two steps: a) pre-calcination of a “green” mixture attemperature of up to about 750° C. in a rotary calciner; and b) hightemperature calcination of the pre-calcined material at a temperature ofat least about 750° C.

An embodiment includes a process for preparing a layered oxide cathodecomposition, said process comprising: pre-calcining a lithium source anda mixed metal precursor in a first rotary calciner to form apre-calcined material; and subjecting said pre-calcined material to hightemperature calcination in a second rotary calciner at a temperature ofat least about 750° C. In an embodiment, the lithium source is selectedfrom the group consisting of lithium carbonate, lithium hydroxide,lithium oxide, lithium chloride, lithium nitrate, lithium sulfate,lithium hydrogen-carbonate, lithium acetate, lithium fluoride, lithiumbromide, lithium iodide, and lithium peroxide. In an embodiment, themixed metal precursor is selected from the group consisting of mixedmetal hydroxides, metal oxy-hydroxides, metal carbonates, and metalhydroxyl-carbonates. In an embodiment, first and second rotary calcinerseach individually has at least two zones. In an embodiment, thepre-calcination step and the high temperature calcination step eachindividually takes place for less than 12 hours. In an embodiment, thepre-calcination step and the high temperature calcination step eachindividually takes place for less than 6 hours. In an embodiment, thepre-calcination step and the high temperature calcination step eachindividually takes place for less than 2 hours. In an embodiment, saideach of said zones has a same or a different temperature from each otherzone. In an embodiment, the mixed metal precursor comprises nickelmanganese cobalt and aluminum, in a ratio of Ni_(x)Mn_(y)Co_(z)Al_(w),where x+y+z+w≦1, and 0≦x<1, 0<y<1, 0<z<1 and 0<w<0.2. In an embodiment,the high temperature calcination comprises: heating said pre-calcinedmaterial to a temperature of at least about 750° C. over a first periodof time; and holding said temperature for a second period of time. In anembodiment, the temperature is at least about 900° C. In an embodiment,the first period of time is about 1 hour or less, and said second periodof time is about 3 hours or less. In an embodiment, the first and secondrotary calciner each individually comprises a metallic tube or a ceramictube. In an embodiment, the pre-calcining and high-temperature calciningsteps have an aggregate duration of about 15 hours or less.

An embodiment of the process includes a process for preparing a layeredoxide cathode composition, said process comprising: pre-calcining alithium source and a mixed metal precursor in a rotary calciner to forma pre-calcined material; and subjecting said pre-calcined material tohigh temperature calcination in a box type furnace at a temperature ofat least about 750° C. In an embodiment, the lithium source is selectedfrom the group consisting of lithium carbonate, lithium hydroxide,lithium chloride, lithium oxide, lithium nitrate, lithium sulfate,lithium hydrogen-carbonate, lithium acetate, lithium fluoride, lithiumbromide, lithium iodide, and lithium peroxide. In an embodiment, themixed metal precursor is selected from the group consisting of mixedmetal hydroxides, metal oxy-hydroxides, metal carbonates and metalhydroxy-carbonates. In an embodiment, the rotary calciner has at leasttwo zones. In an embodiment, the pre-calcination step and the hightemperature calcination step each individually takes place for less than12 hours. In an embodiment, the pre-calcination step takes place forless than 4 hours and the high temperature calcination step takes placefor less than 8 hours. In an embodiment, each of said zones is a same ora different temperatures from each other zone. In an embodiment, saidmixed metal precursor comprises nickel manganese cobalt and aluminum, ina ratio of Ni_(x)Mn_(y)Co_(z)Al_(w), where x+y+z+w≦1, and 0≦x<1, 0≦y<1,0≦z<1 and 0≦w<0.2. In an embodiment, said high temperature calcinationcomprises: heating said pre-calcined material to a temperature of atleast about 750° C. over a first period of time; and holding saidtemperature for a second period of time.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe embodiments, will be better understood when read in conjunction withthe appended drawings. For the purpose of illustration, there are shownin the drawings some embodiments which may be preferable. It should beunderstood, however, that the embodiments depicted are not limited tothe precise arrangements and instrumentalities shown.

FIG. 1 is a powder x-ray diffraction pattern of the green mixture.

FIG. 2 is a powder x-ray diffraction pattern of the green mixture after580° C. rotary pre-calcination in air.

FIG. 3 is a powder x-ray diffraction pattern of the final productobtained after 580° C. pre-calcination followed by 1 hr high temperaturecalcination at 900° C. in a box type furnace.

FIG. 4 is a powder x-ray diffraction pattern of the final productobtained after a 625° C. rotary pre-calcination followed by hightemperature calcination at 910° C., also in a rotary calciner.

DETAILED DESCRIPTION

The present disclosure provides a process for the synthesis of a layeredoxide cathode composition for use in secondary Li-ion batteries. In anembodiment, the process comprises two steps: a) pre-calcination of a“green” mixture in a rotary calciner at temperature up to about 750° C.to obtain a pre-calcined intermediate; and b) high temperaturecalcination of the pre-calcined intermediate at a temperature of aboveabout 750° C. in a rotary calciner. In an embodiment, the processcomprises two steps: a) pre-calcination of a “green” mixture in a rotarycalciner at temperature up to about 750° C. to obtain a pre-calcinedintermediate; and b) high temperature calcination of the pre-calcinedintermediate at a temperature of above about 750° C. in a box typefurnace. In an embodiment, the green mixture comprises one or more mixedmetal precursors and a lithium source.

One example of a suitable mixed metal precursor is a mixed metaloxy-hydroxide, such as Ni_(1/3)Co_(1/3)Mn_(1/3)O_(x)(OH)_(y), which iscommercially available as “X01” from OM Group, Inc. (“OMG”). Otherexamples of suitable mixed metal precursors include, but are not limitedto, metal hydroxides, metal oxy-hydroxides, metal carbonates, and metalhydroxyl-carbonates. Suitable sources of lithium include, but are notlimited to, lithium carbonate (Li₂CO₃), as well as lithium hydroxide,lithium oxide, lithium chloride, lithium nitrate, lithium sulfate,lithium hydrogen-carbonate, lithium acetate, lithium fluoride, lithiumbromide, lithium iodide, and lithium peroxide. In particularembodiments, the lithium source can be lithium carbonate.

In an embodiment, the mixed metal precursor and the lithium source canbe mixed such that the molar ratio of lithium to metal can be from about0.5 to about 2.0, and in other embodiments, from about 0.75 to about1.5. In particular embodiments, the Li to metal ratio can be about 1.15.When calculating the Li to metal ratio, the molar quantity of metal isequal to the sum of the total moles of transition metals present. Forexample, in Ni_(1/3)Co_(1/3)Mn_(1/3)O_(x)(OH)_(y) the moles of metal(assuming 1 mol of total material) is (1/3)*3, or 1. In order to achievea Li/Metal ratio of 1.15, about 0.575 moles of Li₂CO₃ would benecessary.

In an embodiment, the green mixture can be formed by mixing the lithiumand the mixed metal precursor. The green mixture can then pre-calcinedin a rotary calciner. Unlike a typical box furnace or other continuoustype calcination equipment, a rotary calciner induces mixing during thepre-calcining process and exposes the entirety of the green mixture tothe atmosphere of the rotary calcining apparatus. The calcinationatmosphere can be air, oxygen enriched air (i.e. air having an oxygencontent of greater than about 21% by volume), pure oxygen, or otheroxidizing atmosphere. It has been surprisingly found that this mixingstep substantially reduces overall calcining time, as compared, forexample, to calcinations using a roller hearth kiln or other furnace,wherein the green mixture is necessarily held in a static position forthe duration of the calcination process. Without wishing to be bound toany particular theory, it is believed that greater exposure of the greenmixture to the atmosphere of the rotary calciner enhances the reactionrate between the lithium source, mixed metal precursor, and thecalcination atmosphere, such as oxygen.

The duration of the pre-calcination steps and/or high temperaturecalcination steps can each individually or in aggregate be less thanabout 12 hours, and in certain embodiments, less than about 6 hours,less than about 2 hours, or even less than about 1 hour. For example, inan embodiment, the pre-calcination step takes place in less than 12hours and the high temperature calcination step takes place in less than12 hours. In an embodiment, the pre-calcination steps and/or hightemperature calcination steps can each individually or in aggregate befrom about 15 minutes to about 12 hours, and in certain embodiments,from about 15 minutes to about 6 hours, from about 15 minutes to about 2hours, or even from about 15 minutes to about 1 hour. In anotherembodiment, the pre-calcination step takes place in less than 4 hoursand the high temperature calcination takes please for less than 8 hours.In another embodiment, the pre-calcination step takes place in fromabout 15 minutes to less than 4 hours and the high temperaturecalcination takes please for from about 15 minutes to less than 8 hours.

The pre-calcination can be performed at a temperature of at least about750° C. In an embodiment, the pre-calcination step and high calcinationstep can take place in a first and second rotary calciner, wherein thefirst and second rotary calciner can be the same calciner or differentcalciners. In an embodiment, the pre-calcination step and the hightemperature calcination step can each individually comprise more thanone sub-step.

In an embodiment, a given rotary calciner can have one or more zones,including at least two zones. For example, in certain embodiments, therotary calciner can have three to six zones or more. In particularembodiments, the rotary calciner can have three zones. The use of azoned rotary calciner allows for maintenance of a temperature gradient,or alternatively, can be used to provide better temperature control whentrying to maintain a constant temperature throughout the rotarycalciner. In an embodiment, each zone can have the same or a differenttemperature from each other zone.

In an embodiment having three zones, the first zone can have atemperature ranging from about 195° C. to about 330° C., including allwhole and partial increments there between. In particular embodiments,the temperature in the first zone can be about 200° C., 250° C., 300°C., or 325° C.

In particular embodiments, the second and third zones can havetemperatures independently ranging from about 340° C. to about 750° C.,including all whole and partial increments there between. In particularembodiments, the temperatures in the second and third zones can be,independently, about 350° C., 450° C., 500° C., 550° C., 580° C., 600°C., 650° C., 700° C. and 750° C. In particular embodiments, the secondand third zones can have the same temperature.

Rotary pre-calcination can be performed in a rotary calciner having aceramic or a metallic tube. It has been surprisingly found that using arotary calciner having a metallic tube does not increase impurities suchas Fe, Cr, Cu, or Zn in the pre-calcined intermediate. If present,impurities of this nature can impede the performance of the resultinglayered oxide material. In an embodiment, a first and second calcinercan each individually have a ceramic or a metallic tube.

When lithium carbonate is used as the lithium source, the intermediateobtained from the pre-calcination step can contain a small amount ofresidual lithium carbonate, as observed by powder x-ray diffraction(“XRD”). See, e.g., FIG. 2. Without wishing to be bound by anyparticular theory, it is believed that the reduction in residual lithiumsource, and particularly lithium carbonate, partial oxidation oftransition metals and the formation of the intermediate results in anincrease of up to about 60% in the tap density of the resultant powderafter pre-calcination as compared to the green mixture beforepre-calcination.

Powder XRD of the pre-calcined intermediate shows a microcrystallinelayered structure closely resembling the powder XRD pattern of the finalproduct. Despite the structural similarity, to realize optimalfunctionality in a rechargeable battery, the layered structure must befully crystalline. Thus, following pre-calcination, the pre-calcinedintermediate can be subject to high temperature calcination. Hightemperature calcination can be performed at a temperature above about750° C. up to about 1000° C. in an atmosphere comprising air, oxygenenriched air, pure oxygen, ozone or other oxidizing atmosphere. In anembodiment, the high temperature calcination can comprise heating thepre-calcined material to a temperature of at least about 750° C. over afirst period of time and holding the temperature for a second period oftime. In particular embodiments, high temperature calcination can beperformed at a temperature of at least about 900° C.

In certain embodiments, the high temperature calcination can take placeusing saggars, with a calcination profile of about 16 hours attemperature. In certain embodiments, the high temperature calcinationtakes place for less than about 10 hours. In other embodiments, the hightemperature calcination takes about 6 hours, and in further embodiments,about 3 hours. Alternatively, the high temperature calcination can takeplace in a rotary or pendulum type kiln. Processes in these types offurnaces typically require less than about 6 hours, and in certainembodiments, less than about 4 hours, or even less than 2 hours.

The benefits of the above described two step process include asignificant reduction in overall process cost due to higher throughput.Additionally, the above described process allows for the fine tuning ofproduct properties in terms of crystallite size through the appropriateselection of the time and temperature of each step in the process. It isbelieved that the process described herein likewise results in a producthaving greater homogeneity than a layered oxide prepared by prior artprocesses.

Although the process disclosed herein bears some resemblance to theprocess disclosed in U.S. Publication No. 2009/0289218, that process canbe readily distinguished from the process described herein. Inparticular, the process disclosed in U.S. Publication No. 2009/0289218is used for the preparation of spinel type Li—Mn composites according tothe general formula Li_(1+x)Mn_(2−y)M_(y)O₄. A compound of this type, aswell as the precursors used to prepare it, are both chemically andstructurally different from the Li(Li_(a)Ni_(x)Co_(y)Mn_(z))O₂ materialsproduced by the process described herein. Given the substantialdifferences in chemical structure and properties, a skilled artisanwould not have been informed of the process disclosed herein by thedisclosure of U.S. Publication No. 2009/0289218.

What is more, U.S. Pub. No. 2009/0289218 discloses that the spinel typeLi—Mn composite can be prepared in a continuous furnace. Continuousfurnaces are substantially different from the rotary calciner used inthe process described herein. For example, continuous furnaces aretypically embodied by roller hearth kilns or “pusher” type kilns. Bothkilns require the use of saggars, which hold the mixture being calcinedfirmly in one place. The process disclosed herein, though, uses a rotarycalciner during the pre-calcining step. As is described elsewhereherein, a rotary calciner induces mixing during the pre-calciningprocess and exposes the mixture being pre-calcined to the oxygen in thepre-calcining environment. This exposure has surprisingly been found tosubstantially reduce the total amount of time necessary for calcination.The use of a rotary calciner is neither taught nor suggested by U.S.Pub. No. 2009/0289218.

DEFINITIONS

As used herein, each of the following terms has the meaning associatedwith it in this section.

The articles “a” and “an” are used herein to refer to one or to morethan one (i.e., to at least one) of the grammatical object of thearticle. By way of example, “an element” means one element or more thanone element.

As used herein “pure oxygen” refers to a gas comprising at least about99% or more diatomic oxygen by volume.

The term “green mixture” means of amounts of lithium source and a mixedmetal precursor capable of being treated by pre-calcination andcalcination steps to produce a layered oxide composition.

The phrase “enriched oxygen air” means air having an oxygen content ofgreater than about 21% by volume.

The term “about” means ±5% of a given numerical value.

EXAMPLES

The process for preparing the layered oxide disclosed herein is nowfurther described with reference to the following examples. Theseexamples are provided for the purpose of illustration only and thecathode and method for making it disclosed herein should in no way beconstrued as being limited to these examples but rather should beconstrued to encompass any and all variations which become evident as aresult of the teaching provided herein.

Example 1 Pre-Calcination Process and Results

A green mixture consisting of Li₂CO₃ (6.248 Kg) and the mixed metaloxy-hydroxide precursor [Ni_(0.333)Co_(0.333)Mn_(0.333)O_(x)(OH)_(y)](13.565 Kg) was prepared by combining the Li₂CO₃ and[Ni_(0.333)Co_(0.333)Mn_(0.333)O_(x)(OH)_(y)] such that a mixture havinga Li to metal ratio (target) of about 1.15 was formed. The Li to metalratio was calculated based on the total moles of Li to the total molesof transition metal, i.e. the sum of the moles of Ni, Co, and Mn. Theactual mixture was analyzed to contain 5.74% Li, 14.20% Ni, 14.50% Co,and 13.60% Mn by weight. The measured Li/Me ratio was 1.12. The averageoxidation state of transition metals in the green mixture determined byBunsen titration was 2.53.

The green mixture was then subject to rotary calcination in a three zonerotary calciner having a metallic tube. Total residence time in therotary calciner was about 1.5 to about 2.5 hours, with materials movingfreely between the zones due to the rotation of the rotary calciner. Thetemperatures of the individual zones during calcination are shown inTable 1. Table 1 also includes the results of an analysis for Li, Ni,Co, and Mn in the resulting pre-calcined intermediate. These resultsshow that the absolute concentration of Li, Ni, Co, and Mn increasedwith the temperature of the pre-calcination process. This was expectedas CO₂ and H₂O were driven out of the green mixture, resulting in a Liand transition metal enriched intermediate. Analysis of the pre-calcinedintermediate also showed that the Li/Me ratio was about constant andthat Li was not lost due to corrosion of the metallic rotary calcinertube. There was no measureable increase of impurities from the tube suchas Fe, Cr, Cu and Zn found in the pre-calcined intermediates.

Table 1 further shows that the average transition metal oxidation stateafter pre-calcination, measured according to the previously providedprocedure, was greater than about 2.85. This indicates a significantdegree of oxidation of the transition metals, with fully formed layeredoxide material having an oxidation state of about 3.

TABLE 1 Zone 1 Zone 2 Zone 3 Li Ni Co Mn Avg. Ox. Sample (° C.) (° C.)(° C.) (wt. %) (wt. %) (wt. %) (wt. %) Li/Me* State A 200 350 350 5.8515.00 15.40 14.20 1.09 2.89 B 250 350 450 6.45 16.10 16.30 15.20 1.122.86 C 250 450 450 6.88 16.80 17.20 15.90 1.14 2.91 D 300 500 500 7.2818.00 18.30 17.00 1.13 2.93 E 325 550 550 7.67 18.50 19.20 17.80 1.152.95 F 325 580 580 7.66 18.60 19.20 18.00 1.14 2.95 *= molar ratio; Me =Ni + Co + Mn

Example 2 High Temperature Calcination in a Box Type Furnace

The materials produced in the pre-calcination process were then subjectto high temperature calcination in a box type furnace according to theconditions set forth in Table 2, in air. An exemplary powder XRD of theresulting final material is shown in FIG. 3. The resulting materialswere analyzed to have the Li, Ni, Co, and Mn contents shown in a givenrow. Li to metal ratios were likewise calculated for the final product.Loss on ignition (“LOI”) was also calculated. LOI (weight %) wasdetermined by weighing a sample, heating the sample to 800° C., andweighing the sample again. Any observed weight loss provided anapproximation of the amount of free lithium carbonate and/or hydroxidein the high temperature calcined material.

TABLE 2 Target Ramp Dwell Li Ni Co Mn LOI Feed temp. (° C.) (h) (h) (wt.%) (wt. %) (wt. %) (wt. %) Li/Me* (%) E 950 2 4 7.68 19.90 20.40 18.801.08 0.42 F 950 2 2 7.78 19.80 20.40 19.00 1.09 0.38 G 900 2 2 7.7919.60 20.30 18.50 1.11 0.4 H 900 2 1 7.90 20.00 20.40 18.80 1.11 0.48 I900 2 4 7.89 19.90 20.37 18.56 1.11 0.35 J 900 2 2 7.72 19.60 20.0018.40 1.10 0.44 K 900 2 1 7.85 19.90 20.30 18.69 1.11 0.49 L 900 2 47.93 20.20 20.50 18.90 1.10 0.42 *= molar ratio; Me = Ni + Co + Mn

Example 3 High Temperature Calcination in a Rotary Calciner

A green mixture was prepared according to the procedure set forth inExample 1. This mixture was then pre-calcined at 625° C. in flowing airatmosphere. The resulting pre-calcined intermediate was then immediatelysubjected to a three-zone high temperature calcination in a rotarycalciner having a flowing air environment. Calciner temperature zonesettings are set forth in Table 3.

TABLE 3 Temperature Zone (° C.) 1 700 2 910 3 910

The overall residence time of the pre-calcined intermediate in the hightemperature rotary calciner was about 1 hr. The resulting final layeredoxide product of this process was a highly crystalline materialidentical in structure to materials produced according to the standardmethodology. See, for example, FIG. 4.

The resulting product was also analyzed to determine the level ofimpurities contained therein. Two types of samples were used todetermine the quantity of impurities. Sample A was taken from thematerial collected during first about 15 minutes of the productdischarge from the calciner. Sample B was then taken from the bulk ofthe material collected during the rest of the high-temperature rotarycalcination process.

TABLE 4 Mate- Li Ni Co Mn Li/ Cr Fe rial (wt. %) (wt. %) (wt. %) (wt. %)Me* (ppm) (ppm) Sample 8.07 19.90 20.30 18.90 1.13 26 31 A Sample 7.9520.30 20.60 18.60 1.11 <10 <10 B *= molar ratio; Me = Ni + Co + Mn

Both the Sample A and the Sample B showed Li/Me ratios consistent withthe intermediate compositions and thus no loss of lithium in the tube.Fe and Cr impurities, however, varied between the Sample A and B.Specifically, the Sample A contained slightly elevated quantities of Feand Cr at 31 ppm and 26 ppm, respectively. Conversely, the Sample Bshowed no measureable increases in Fe and Cr versus samples subject tohigh temperature calcination in non-rotary type calciners.

Without wishing to be bound to any particular theory, it is believedthat the difference in Fe and Cr concentration in Sample A and Sample Bis due to the formation of an initial sacrificial coating in the tube ofthe rotary calciner in the beginning of the process. As this coatingforms, subsequent materials are not directly exposed to the metallictube and thus do not contain increased levels of these undesiredimpurities.

The disclosures of each and every patent, patent application, andpublication cited herein are hereby incorporated herein by reference intheir entirety.

While reference has been made to specific embodiments, it is apparentthat other embodiments and variations can be devised by others skilledin the art without departing from their spirit and scope. The appendedclaims are intended to be construed to include all such embodiments andequivalent variations.

1. A process for preparing a layered oxide cathode composition, saidprocess comprising: pre-calcining a lithium source and a mixed metalprecursor in a first rotary calciner to form a pre-calcined material;and subjecting said pre-calcined material to high temperaturecalcination in a second rotary calciner at a temperature of at leastabout 750° C.
 2. The process of claim 1, wherein said lithium source isselected from the group consisting of lithium carbonate, lithiumhydroxide, lithium oxide, lithium chloride, lithium nitrate, lithiumsulfate, lithium hydrogen-carbonate, lithium acetate, lithium fluoride,lithium bromide, lithium iodide, and lithium peroxide.
 3. The process ofclaim 1, wherein said mixed metal precursor is selected from the groupconsisting of mixed metal hydroxides, metal oxy-hydroxides, metalcarbonates, and metal hydroxyl-carbonates.
 4. The process of claim 1,wherein said first and second rotary calciners each individually has atleast two zones.
 5. The process of claim 1, wherein the pre-calcinationstep and the high temperature calcination step each individually takesplace for less than 12 hours.
 6. The process of claim 5, wherein thepre-calcination step and the high temperature calcination step eachindividually takes place for less than 6 hours.
 7. The process of claim5, wherein the pre-calcination step and the high temperature calcinationstep each individually takes place for less than 2 hours.
 8. The processof claim 4, where said each of said zones has a same or a differenttemperature from each other zone.
 9. The process of claim 1, whereinsaid mixed metal precursor comprises nickel manganese cobalt andaluminum, in a ratio of Ni_(x)Mn_(y)Co_(z)Al_(w), where x+y+z+w≦1, and0≦x<1, 0≦y<1, 0≦z<1 and 0≦w<0.2.
 10. The process of claim 1, whereinsaid high temperature calcination comprises: heating said pre-calcinedmaterial to a temperature of at least about 750° C. over a first periodof time; and holding said temperature for a second period of time. 11.The process of claim 10, wherein said temperature is at least about 900°C.
 12. The process of claim 10, wherein said first period of time isabout 1 hour or less, and said second period of time is about 3 hours orless.
 13. The process of claim 1, wherein said first and second rotarycalciner each individually comprises a metallic tube or a ceramic tube.14. The process of claim 1, wherein the pre-calcining andhigh-temperature calcining steps have an aggregate duration of about 15hours or less.
 15. A process for preparing a layered oxide cathodecomposition, said process comprising: pre-calcining a lithium source anda mixed metal precursor in a rotary calciner to form a pre-calcinedmaterial; and subjecting said pre-calcined material to high temperaturecalcination in a box type furnace at a temperature of at least about750° C.
 16. The process of claim 15, wherein said lithium source isselected from the group consisting of lithium carbonate, lithiumhydroxide, lithium chloride, lithium oxide, lithium nitrate, lithiumsulfate, lithium hydrogen-carbonate, lithium acetate, lithium fluoride,lithium bromide, lithium iodide, and lithium peroxide.
 17. The processof claim 15, wherein said mixed metal precursor is selected from thegroup consisting of mixed metal hydroxides, metal oxy-hydroxides, metalcarbonates and metal hydroxy-carbonates.
 18. The process of claim 15,wherein said rotary calciner has at least two zones.
 19. The process ofclaim 15, wherein the pre-calcination step and the high temperaturecalcination step each individually takes place for less than 12 hours.20. The process of claim 15, wherein the pre-calcination step takesplace for less than 4 hours and the high temperature calcination steptakes place for less than 8 hours.
 21. The process of claim 18, wheresaid each of said zones is a same or a different temperatures from eachother zone.
 22. The process of claim 16, wherein said mixed metalprecursor comprises nickel manganese cobalt and aluminum, in a ratio ofNi_(x)Mn_(y)Co_(z)Al_(w), where x+y+z+w≦1, and 0≦x<1, 0≦y<1, 0≦z<1 and0≦w<0.2.
 23. The process of claim 16, wherein said high temperaturecalcination comprises: heating said pre-calcined material to atemperature of at least about 750° C. over a first period of time; andholding said temperature for a second period of time.